Lead researcher Andrea Meltzer and her team at Florida State University examined data from two independent longitudinal studies, one with 96 newlywed couples and another with 118 newlywed couples. All the couples had completed at least three consecutive days of a 14-day sex diary.

Each night before falling asleep, the partners were asked to report whether they had sex that day. They were also asked to jot down how satisfied they were with three things: their sex life, their partner and their relationship as a whole.

On average, the participants had sex four days out of the 14. Unsurprisingly, sex on any given day was linked with feelings of sexual and relationship satisfaction ― but what’s interesting is that the afterglow effect lasted up to 48 hours later. And those who sustained the afterglow for that amount of time also were happy with their relationships months down the road.

“"People with a stronger sexual afterglow ― that is, people who report a higher level of sexual satisfaction 48 hours after sex ― report higher levels of relationship satisfaction several months later."”

- Andrea Meltzer

“People with a stronger sexual afterglow ― that is, people who report a higher level of sexual satisfaction 48 hours after sex ― report higher levels of relationship satisfaction several months later,” Meltzer said of the study, which was published this month in Psychological Science, a journal of the Association for Psychological Science.

In an interview with The Huffington Post, Meltzer said what most surprised her most about the findings was how well the mental benefits of sex synced up with human biology.

“Forty-eight hours is roughly the same amount of time that (a) conception is maximized, (b) it takes sperm concentrations to be restored to peak levels, and (c) sperm remain maximally viable in the female reproductive tract,” she said. “It’s really interesting that lingering cognitive implications of sex ― sexual afterglow, for instance ― last for the same amount of time as the biological implications of sex.”

Meltzer said that newlyweds were singled out for the study because they engage in sex more frequently than long-term couples ― a requisite for the research.

“Our theory was based on reproduction,” Meltzer told HuffPost. “Given that newlyweds are often young and of reproductive age, they were an ideal sample in which to test our predictions.”

In sum? Sex plays a major role in satisfaction and pair bonding, even if you’re not having sex every day of the week.